A technique for calculating an acoustic characteristic correction coefficient based on an impulse response is known. For example, a sound wave corresponding to an acoustic characteristic measurement signal (impulse, TSP or white noise) is output by use of a to-be-measured acoustic output unit and the sound wave is input by use of an acoustic input unit of an acoustic characteristic correction coefficient calculation apparatus and converted to an electrical signal. A transfer function corresponding to a portion ranging from the to-be-measured acoustic output unit to the acoustic output unit of the acoustic characteristic correction coefficient calculation apparatus is calculated. Then, an inverse transfer function of the transfer function is calculated and an impulse response corresponding to the inverse transfer function is acquired. Further, the impulse response is cut out by a preset tap number and an acoustic characteristic correction coefficient can be calculated. For example, a correction filter utilizing the above calculated acoustic characteristic correction coefficient is applied to an acoustic apparatus to improve the sound quality of the acoustic apparatus.
It is known that it takes certain time for the thus acquired impulse response to be sufficiently converged. If the impulse response is cut out by the limited preset tap number, the cutout result may correspond to an impulse response that is not sufficiently converged. An acoustic characteristic correction coefficient calculated based on the cutout result corresponding to the impulse response that is not sufficiently converged may not be an adequate correction coefficient in some cases.